South Korea’s Toss Bank (토스뱅크) experienced a transfer error for about 30 minutes on the afternoon of October 7. Some transfers from other financial institutions failed, but the funds still appeared in Toss Bank accounts. (ETNews) A reporter tested the issue by transferring 5,000 won through Naver Pay four times. A total of 20,000 won was credited, while nothing was deducted from the sending account. (Previously: A string of cyberattacks on South Korean banks; government points to traces of a “Chinese AI hacking tool”) (Background: Bithumb mistakenly issued 620,000 BTC; a second South Korean court ruling says “users must return the proceeds from selling the coins”) Key points: Failed transfers were still credited to Toss Bank accounts for about 30 minutes on the 7th. An ETNews test found that four transfers of 5,000 won each resulted in a total credit of 20,000 won. Toss Bank said the error on the 7th was caused by an internal system update. South Korea’s Toss Bank (토스뱅크) experienced a transfer error on the afternoon of October 7. The problem affected transactions transferring funds from other financial institutions into Toss Bank. Some transactions had clearly failed, yet the money was still credited to Toss Bank accounts. South Korean media outlet News1 (뉴스1) reported that the system error began at around 2:20 p.m. Korea time and lasted about 30 minutes. ETNews (전자신문) reported that the error occurred between 2:20 p.m. and 2:50 p.m. Korea time. That day, an ETNews reporter tested the issue by transferring 5,000 won in Naver Pay balance to a Toss Bank account. The Naver Pay app displayed the message “Transfer failed. The transfer has been canceled,” but the money arrived in the Toss Bank account. The 5,000 won was still available in Naver Pay and could be transferred again. ETNews repeated the same steps three more times, and the error persisted. The 5,000 won balance was never deducted, while the Toss Bank account received a total of 20,000 won—meaning the same 5,000 won balance was credited four times. ETNews confirmed that the problem was with Toss Bank and was unrelated to Naver Pay. Toss Bank says an internal system update caused the error. Toss Bank said the error was “confirmed to have occurred during an internal system update” and that “it was fixed immediately after being identified, and the service is now operating normally.” Toss Bank also said this was a “simple error” and was not caused by an external intrusion such as a hacker attack. An unnamed Toss Bank official told ETNews that the error occurred because “a single transfer request was processed multiple times.” South Korean banks have recently suffered a series of personal data leaks caused by AI-powered hackers. Toss Bank said this system failure “was unrelated to AI hackers.” There’s no such thing as free money. Toss Bank said transactions credited in error would be corrected in accordance with relevant laws and terms, and affected customers would be notified individually. Once corrected, the transactions can be seen in the transaction history. Toss Bank also said it was conducting a detailed analysis of the exact cause and would comprehensively review and improve its systems to prevent a recurrence. When ETNews reported on the afternoon of the 7th, transfers had returned to normal, but the amounts credited in error had not yet been recovered. The report expected that once the cancellation process began, the funds would be handled as canceled transfers in due course. Under South Korea’s Electronic Financial Transactions Act, financial institutions must promptly investigate and address transaction errors they discover. ETNews also noted that the Supreme Court of South Korea has ruled that when a bank deposits money into a customer’s account by mistake, the bank may correct the deposit record and reverse the transfer unless there are special circumstances. Frequently asked questions: How did the Toss Bank transfer error happen? Toss Bank said the error, which lasted about 30 minutes on the afternoon of October 7, occurred during an internal system update. A single transfer request was processed multiple times, and the incident was unrelated to a hacker intrusion. Will the money mistakenly credited by Toss Bank be recovered? Toss Bank said it would correct transactions credited in error in accordance with laws and terms, and notify customers individually. At the time of ETNews’ report on the 7th, the money had not yet been recovered. The report did not specify the number of affected transactions or the amount involved. Related reports: South Korea’s central bank steps in: Crypto exchanges to be required to introduce circuit breakers to prevent another $42 billion Bithumb Bitcoin blunder. Bithumb reviews “620,000 BTC mistaken transfer incident”: Internal system had serious flaws and was vulnerable to potential sabotage. South Korea’s five largest exchanges suffered 57 incidents over six years, with losses of 7 billion won; regulators consider legislation requiring operators to compensate users unconditionally. This article, “Toss Bank system update goes wrong in South Korea; ‘failed transfers’ can be used to print money endlessly,” was first published by BlockTempo (動區動趨—The Most Influential Blockchain News Media).